Claude Opus 5.5 vs GLM-5.3
Wins 6 of 7 areas
Coding · Agents · Reasoning · Facts · Math · Long documents
Wins 1 of 7 areas
Following instructions
Claude Opus 5.5 is the stronger all-rounder.GLM-5.3 is cheaper and better at following instructions.
Both rank among the ten best models we track in agents.
Scores updated · 38 tests both models report · How we compare
Where each one wins
Tests won in each of the seven areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software40Claude Opus 5.54 of 4 tests
- ReasoningHard problems that need careful thinking40Claude Opus 5.54 of 4 tests
- MathCompetition and research-level math30Claude Opus 5.53 of 3 tests
- AgentsCarrying out multi-step tasks on its own21Claude Opus 5.52 of 3 tests
- FactsGetting facts right instead of making them up21Claude Opus 5.52 of 3 tests
- Long documentsFinding answers in very long texts10Claude Opus 5.51 of 1 test
- Following instructionsDoing exactly what it is asked01GLM-5.31 of 1 test
Long documents and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
GLM-5.3 costs 76% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where Claude Opus 5.5 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+65.7points ahead
- Answers hard knowledge questions correctlyAA-Omniscience · Accuracy+32.3points ahead
- Short factual questions, answered correctlySimpleQA Verified+31.2points ahead
Where GLM-5.3 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+29points ahead
- Finds the root cause of IT system incidentsAA IT-Bench SRE+7.9points ahead
- Follows detailed instructions exactlyLiveBench · Instruction Following+3.6points ahead
Every test, side by side
All 38 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 5.5
- LMArena · WebDevClaude Opus 5.5 by 196 rating points18181622+196 rating
- LiveBench · Agentic CodingClaude Opus 5.5 by 10.871.760.9+10.8
- LiveBench · CodingClaude Opus 5.5 by 10.389.379+10.3
- SciCodeClaude Opus 5.5 by 7.966.959+7.9
AgentsClaude Opus 5.5
- Terminal-Bench 4.0Claude Opus 5.5 by 17.759.641.9+17.7
- GDPValClaude Opus 5.5 by 10.868.357.5+10.8
- AA IT-Bench SREGLM-5.3 by 7.938.246.1+7.9
ReasoningClaude Opus 5.5
- SimpleBenchClaude Opus 5.5 by 22.288.466.2+22.2
- Humanity's Last ExamClaude Opus 5.5 by 19.161.442.3+19.1
- CritPtClaude Opus 5.5 by 12.631.719.1+12.6
- LiveBench · ReasoningClaude Opus 5.5 by 6.492.285.8+6.4
FactsClaude Opus 5.5
- AA-Omniscience · AccuracyClaude Opus 5.5 by 32.366.233.9+32.3
- SimpleQA VerifiedClaude Opus 5.5 by 31.272.241+31.2
- AA-Omniscience · Non-hallucinationGLM-5.3 by 2941.470.4+29
MathClaude Opus 5.5
- FrontierMath Tier 4Claude Opus 5.5 by 65.79529.3+65.7
- FrontierMath Tiers 1-3 (v2)Claude Opus 5.5 by 22.491.268.8+22.4
- LiveBench · MathematicsClaude Opus 5.5 by 9.297.187.9+9.2
Following instructionsGLM-5.3
- LiveBench · Instruction FollowingGLM-5.3 by 3.665.769.3+3.6
Other results19 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- Program BenchClaude Opus 5.5 by 72.291.219+72.2
- HLE-DiamondClaude Opus 5.5 by 5067.917.9+50
- Terminal-Bench-Science 0.1Claude Opus 5.5 by 49.5599.5+49.5
- CritPt v2 HardClaude Opus 5.5 by 34.56833.5+34.5
- AA-OmniscienceClaude Opus 5.5 by 32.146.414.3+32.1
- Terminal-Bench 4.0Claude Opus 5.5 by 24.666.441.8+24.6
- GDP (Surge AI)Claude Opus 5.5 by 1526.211.2+15
- AA IntelligenceClaude Opus 5.5 by 12.857.644.8+12.8
- livebench_data_analysisClaude Opus 5.5 by 10.180.370.2+10.1
- PostTrainBenchClaude Opus 5.5 by 9.549.339.8+9.5
- PostTrain Bench v1.2Claude Opus 5.5 by 9.343.834.5+9.3
- DeepSWE 1.1Claude Opus 5.5 by 7.374.266.9+7.3
- HealthBench ProfessionalClaude Opus 5.5 by 7.159.952.8+7.1
- livebench_languageClaude Opus 5.5 by 6.486.379.9+6.4
- HLE (with tools)Claude Opus 5.5 by 5.267.762.5+5.2
- Toolathlon VerifiedClaude Opus 5.5 by 4.877.873+4.8
- SWE Marathon v1.1Claude Opus 5.5 by 3.846.342.5+3.8
- HealthBenchClaude Opus 5.5 by 2.55754.5+2.5
- HiL-Bench (Tools-allowed)tie5958.3tie
Questions people ask
Which is better, Claude Opus 5.5 or GLM-5.3?
Claude Opus 5.5 wins six of the seven areas where both have results: coding, agents, reasoning, facts, math and long documents. GLM-5.3 wins following instructions, and costs 76% less.
Which is better for coding?
Claude Opus 5.5. It wins 4 of the 4 coding tests both models report; GLM-5.3 wins none.
Which is cheaper?
Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; GLM-5.3 costs $1.40 and $4.40. That makes GLM-5.3 about 76% cheaper for the same work.
How do you compare the two?
We use the 38 benchmark tests both models have published scores on. The verdict counts the 19 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 19 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.